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EFI vs carburetors
Posted by: Philippe ()
Date: January 06, 2018 08:20AM

Sorry folks, I am sure that over the years this has been beaten to death. I have been lurking at the MSD 4 barrel type of EFI unit to replace my 4 carb system. My question is is there any benefit in doing this. Some folks on another forum have been adamant; the carbs if well tuned work better. What should I think? Is it worth the $1000/$1500 investment

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Re: EFI vs carburetors
Posted by: Wagon Master ()
Date: January 06, 2018 08:27AM

Are you lurking at a system with four individual injectors monted in pots in place of the factory carbs. or a center mount 4bbl. carb. replacement unit?

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Re: EFI vs carburetors
Posted by: BobV66Vair ()
Date: January 06, 2018 10:10AM

EZEFI from American Pi. Proven system with good support. EFI is more efficient than carbs. Computer controlled fuel delivery, tuned with a smart phone and can be tuned for performance or mileage. Starts instantly and automatically compensates for most things a carb would fail at. Produces more HP due to superior fuel/air mix. Check them out. Worth the money. [www.american-pi.com]

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: EFI vs carburetors
Posted by: Chilly Willy ()
Date: January 06, 2018 10:16AM

The easiest is the tedd Brown Corvair specific.
I put a Fitech on a 302. Started great and ran solid during cam break in, then the problems started. If you want to use the center mount.Any of the big named small efi’s can work but it will take a lot of time tweaking. Even Carbs take a lot of tweaking to get close. Always factor your driving style in your decisionwinking smiley




The Corvair, Keeping Nader Notorious winking smiley


Will
Northern California

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Re: EFI vs carburetors
Posted by: Philippe ()
Date: January 06, 2018 11:50AM

Hi,
I am looking at this
[www.summitracing.com]
That is the 4 barrel single throttle body.

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Re: EFI vs carburetors
Posted by: BobV66Vair ()
Date: January 06, 2018 12:37PM

That's a solid option for a center mount. should be easier to tine than any carb.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: EFI vs carburetors
Posted by: gnvair ()
Date: January 06, 2018 12:42PM

The Holley Sniper or FAST EZ Efi are also good units. The big problem with all of those 4 barrel efi systems is they are designed for V8 engines. The throttle bodies are more than double the cfm that most Corvair engines need. A stock Rochester carb flows about 95 cfm so even a 140 would have 380 cfm. If it's a non performance application and you don't want to have to do tweaking then I would recommend Ted Brown's system
As it is the only true bolt on EFI system for a Corvair.

Lee J



Edited 1 time(s). Last edit at 01/06/2018 12:46PM by gnvair.

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Re: EFI vs carburetors
Posted by: Seth Emerson ()
Date: January 06, 2018 01:05PM

For reference, Both Holley and FItech have announced a 2-barrel replacement, learning system. They bolt onto the Holley 4412 2-barrel pattern. It will be better suited toward a smaller motor - but still a center mount set-up.

[www.youtube.com] - Covers the Holley system

Seth Emerson

Check my new Performance Corvair Web site [www.perfvair.com]

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Re: EFI vs carburetors
Posted by: Philippe ()
Date: January 06, 2018 01:35PM

Thanks Seth (and others before him). The 2 barrel units designed for smaller engine look like a promising option indeed.

Thanks.



Edited 1 time(s). Last edit at 01/06/2018 01:38PM by Philippe.

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Re: EFI vs carburetors
Posted by: JimBrandberg ()
Date: January 08, 2018 04:40AM

Any center mount will still have the air/fuel mixture going through turns in a foot or more of cold manifold. I wonder how an oxygen sensor reacts when fuel puddles out of the atomized mixture. The fuel/air mixture makes a 75 degree bend right away and then another 120 degree bend just before the intake valve. At least the second bend is warmer.
I'm not anti-center mount, I have a 6-tube 390 Holley on my road racing Corvair. The aluminum plenum is ice cold to the touch on a 90 degree day. I've been told that the cold results from the puddled fuel evaporating away from the aluminum. Racing is a lot of WOT driving and it runs good so I haven't worried about it.
There are folks making a warm oil chamber under the plenum, I'm not sure that is ideal but I can't argue against real life testimony.
The EFI I started making but haven't finished is a center mount air only throttle body on a 6-tube manifold with 6 injectors at the bottom. The project stalled when my racecar ate one of the 6-tube heads when I installed them as spares.
$999 to begin is a lot to spend if you don't get really good results.
I've been anti-500 CFM 2 barrel carburetors on Corvairs because our small engine just doesn't promote the velocity through the venturi needed for low speed operation. I suppose a 2-barrel EFI is a different animal if it doesn't depend on airflow to promote fuel mixture.
I'm a little rusty on my EFI speak but do these throttle bodies run on just an O2 sensor or speed density or manifold absolute pressure or ...?
I think folks have just put a coolant temperature sensor in the "room" above the lower shrouds, of course that goes away if you're not running lower shrouds.
I could be off base here but I love a good fuel injection discussion. I probably have more questions than answers. If going with a not Corvair specific system, I would want to pretty much reason it all through before the purchase.
Jim Brandberg
Isanti, MN
CorvairRepair.com

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Re: EFI vs carburetors
Posted by: gnvair ()
Date: January 08, 2018 05:03AM

I am not a fan of throttle body injection as you still have fuel in the intake runners. I especially am not a fan of having the injectors so far away from the intake valve. But for using tbi I think Ted's set up is the best engineered out there as it still keeps the injectors relatively close to the valves and includes ignition controls.
But I see why guys are trying to go with the other set ups and that is because the initial buy in of the other set ups are cheap. Ted's set up is not cheap; but it a complete kit that is proven and works.
But the other set ups still require you to buy other items after the initial buy in. So you still have to procure a 2 or 4 barrel style intake manifold, figure out some kind of intake heating to prevent icing and fuel drop out, throttle linkage modifications, timing mapping (I would not do EFI without having ecm control of it) and other details.
Throttle body size still has an effect on efi as too large a throttle body can make the throttle response feel "laggy"

Lee J

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Re: EFI vs carburetors
Posted by: wv-geo ()
Date: January 08, 2018 05:54AM

Tedd Brown is working on a 140HP EFI system that has four individual throttle bodies mounted where the stock carbs are located.

He's hoping to have it running by this Spring.

Check his site out:

[www.corvair-efi.com]

Dan Stark
Hurricane, WV

1961 Lakewood 500, 80HP, PG
1964 Corvair 500 Coupe, 140HP, 4spd (Christine)
1965 Mustang Coupe, 6cyl, 3spd

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Re: EFI vs carburetors
Posted by: TedBrown ()
Date: January 08, 2018 06:55AM

I am not a fan of center mount either for the same reasons as above. For a race car I can see it, but for a daily, dependable driver that starts and runs, then I would be more hesitant. Will a center mount TBI controlled by a computer have better manners than I center mount venturi type carb... of course, but some of those negative (moderate to cold weather) issues are shared by their Carb cousins.

You can think of TBI as a pressurized Carb. EFI does not make power, it just allows that power to be present/available more than a Carb/manual distributor is capable of. Carbs and Distributors are a compromise between low idle, high vacuum and vise-versa. (Even a broke clock is right 2 times a day). There are sweet spots where a carb and manual distributor are producing perfect burn and power, but that "sweet spot" is not that large. EFI allows the "sweet spot" to be spread through out the RPM and vacuum (load) band and adjust itself based on engine and environmental conditions. EFI can increase/restrict fuel based on many conditions but the low pressure at the venturi is not one of those.

The current EFI system was developed only for the Corvair and the ECM (which is from a 8 Cyl 1500 GM truck) was re-written just for this purpose. The current system is not cheap, but when you take into account it pretty much includes everything you need to install (-fuel pump and return line), its not that expensive. Also keep in mind that I have a re-seller (Clarks) and everything cost money. I will never recoup the money and time I put into this product, but I am happy because it funds my hobby and has been the most commercially successful EFI kit so far (68 units produced). Just as another note, I am NOT increasing wholesale cost again this year. Making EFI inexpensive has always been my goal and when you compare it to other EFI setups (Total cost), I would dare say mine comes in the lowest or very close.

Is EFI perfect...no more than I am, but I always try to correct then tune when I find an issue. The 4xTBI that is under development and testing will give the 140 people (I think) what they want. I am very excited about the new project, but these unit will not be for sale until 2019 as testing cold and hot weather takes a long time/Fuel (GM wont let me use their environmental chamber). Working out computer, timing, parts availability, manufacturing and most important to Corvair people...COST

Do I think every Corvair should have EFI....of course not. I drive only Corvairs on a daily basis as part of my business and I want them as dependable in starting and running as my wifes new car. My intent here is not to start a debate of EFI vs Carbs as debates here yield little. Again.. if you love your Carb and points, please keep them as its not my job to change your thoughts, but for the people who want better performance, start, run, stop for daily drivers, Brown (Clarks) EFI might be for you.

Respectfully submitted.

Ted
www.corvair-efi.com

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Re: EFI vs carburetors
Posted by: jmaechtlen ()
Date: January 08, 2018 09:04PM

A couple of thoughts -
Advantages of efi?
Should run fine even at high or low altitudes, cause the computer knows how much air the engine is actually getting, and what temperature it is.

Since the fuel is getting squirted into the manifold, it should mix better with the air even when things are cold.

I agree with the others about keeping the injectors close to the valves.

Disadvantages?
Cost
breaker points and carburetors don't need computers.

A good carb and point setup can be just fine, aside from possible high altitude issues. But a good efi system can be great.

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Re: EFI vs carburetors
Posted by: American Mel ()
Date: January 08, 2018 09:51PM

Philippe, I would have to ask one question first.
What is your intended purpose/use of your Corvair?
Are you going to daily drive it?
Drive it just to shows and club events?
Auto-cross it?
Take it to the local drags?
Strictly Sunday afternoon cruises to get an Ice-cream with your favorite lady?

Many different things to consider before one can say that one system is better over another.

Consider what Ted Brown himself just said above.
"EFI does not make power, it just allows that power to be present/available more than a Carb/manual distributor is capable of."


There is one egotistical ignoramus on here that claims that anyone and everyone that does not already own a T.B. EFI is an idiot!
Just wasting the time to make that claim shows just how STUPID he is!
The T.B. EFI is undoubtedly the best available for most of us right now.
But there is a couple things to consider.
The T.B. EFI for the 140 is currently running $1600.oo!
And that is only 2 throttle bodies.
When the final product comes out, the one that will let the 140 breath to its full potential, you may upgrade.
But what will the final cost be?
I am guessing over $2000.oo
Some people say that EFI will improve you MPG.
BUT . . . . . . . .
If your Corvair is something that you use for anything less than daily driving, then it will take a LOOOOOOOONNG time to pay for itself ! ! !
Do the math!

I am NOT against the T.B. EFI, I just think that one should count the total, complete, and long term cost of the choice to go EFI or not.
Now, if you have pockets with no bottom, and money is no object, then by all means, do not hesitate!
ORDER one TODAY ! ! !
If I was in a position that I did not have to be concerned about how much money I dropped on my Corvairs, then I would put Ted's system in each of my Vairs and also have Duane W. do a no dime spared restoration on my Vert.
Unfortunately, I have short pockets that are usually empty.eye rolling smiley
But the happiness and grins I get driving my CARBURETED Vairs to their fullest potential is something I can live with ! smiling bouncing smileythumbs upcool smileythumbs up


"My question is, is there any benefit in doing this? Some folks on another forum have been adamant; the carbs if well tuned work better. What should I think? Is it worth the $1000/$1500 investment?"

To truly answer your original question correctly, we really need to know what is your intended use?

.
-----------------------------------------------
WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
'66 Monza Coupe - 4spd, 140 Daily driver beater
'67 Monza Vert. - PG, 140 Daily driver beater

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Re: EFI vs carburetors
Posted by: DAVECS1 ()
Date: January 08, 2018 10:16PM

A correctly installed and calibrated EFI System will not give you anymore power than a correctly installed and tuned set of carbs, so why would someone go to the problem of doing it?

1. Startup in all tempratures, EFI if setup correctly, just requires the flick of a key, no setting the choke or pumping the pedal, and it does not need a long high idle.

2. Running correctly in all weather and elevation. Super humid day efi works, 30F on a chilly fall morning EFI works.

3. If EFI is running the ignition also, there is less maintainence. With less fuel over run and the ability to alter the timjng curve with throttle input, you can keep the plugs extremely clean in all conditions. HEI and Crank trigger pieces have a long service life

4. With good fuel and good timing the oil stays cleaner, add a modern crank case vent system and the engine in general and the oil stay cleaner.

A properly setup carburation system has decent driveability on engines that are not overly modified, so much so, I would be willing to bet one could not tell the difference once the engine was warm and running. In some cases it may have a more desirable response to transient fueling.

With that being said, one of the issues that drove me batty was syncing the carbs and looking after the plethra of linkages that needed to be set just right to get good 110 dual carb performance. This was a regular chore, after a couple thousand miles of driving. Now I have a single throttlebody with an intake and no linkage to worry about.

1964 Monza Convertible
110 4 speed
Peoria, IL




Edited 2 time(s). Last edit at 01/08/2018 10:26PM by DAVECS1.

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Re: EFI vs carburetors
Posted by: gnvair ()
Date: January 09, 2018 06:15AM

A lot of people do not read.
The debate was not whether efi was better than a carburetor.
The big debate was mounting of an aftermarket 4 barrel tbi system on a 4 barrel style intake with the injectors over the fan.
You still have the long runners to contend with and the injectors would be very far from the ports.
Keeping the injectors as close to the intake valve would prevent a whole variety of drivability problems.

Lee J

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Re: EFI vs carburetors
Posted by: Chilly Willy ()
Date: January 09, 2018 07:50AM

gnvair Wrote:
-------------------------------------------------------
> A lot of people do not read.
> The debate was not whether efi was better than a
> carburetor.
Yep. Some people don’t read 😆




The Corvair, Keeping Nader Notorious winking smiley


Will
Northern California

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Re: EFI vs carburetors
Posted by: American Mel ()
Date: January 09, 2018 10:18AM

You are correct!
Some people don't read.
Because it was actually 3 (Three) questions!

"My question is, is there any benefit in doing this? Some folks on another forum have been adamant; the carbs if well tuned work better. What should I think? Is it worth the $1000/$1500 investment?"

.
-----------------------------------------------
WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
'66 Monza Coupe - 4spd, 140 Daily driver beater
'67 Monza Vert. - PG, 140 Daily driver beater

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Re: EFI vs carburetors
Posted by: DAVECS1 ()
Date: January 09, 2018 10:37AM

A throttle body injection setup my work with long runners just fine. You can stage the injection time based on the Firing sequence. With a large enough propagation delay, you may be able to account for throttle lag. Also long runners will give the fuel adequate time to mix well. Also if you control the timing you could mitigate some of the lag issues. It would be best to run a very flexible control system, like a microsquirt.

1964 Monza Convertible
110 4 speed
Peoria, IL

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